1. Field of the Invention
Embodiments of the present invention relate to apparatus and method for polishing semiconductor substrates.
2. Description of the Related Art
Sub-micron multi-level metallization is one of the key technologies for the next generation of ultra large-scale integration (ULSI). The multilevel interconnects that lie at the heart of this technology require planarization of interconnect features formed in high aspect ratio apertures, including contacts, vias, trenches and other features.
Planarization is generally performed using Chemical Mechanical Polishing (CMP) and/or Electro-Chemical Mechanical Deposition (ECMP). A planarization method typically requires that a substrate be mounted in a carrier head, with the surface to be polished exposed. The substrate supported by the carrier head is then placed against a rotating polishing pad. The carrier head holding the substrate may also rotate, to provide additional motion between the substrate and the polishing pad surface. A polishing solution is usually supplied to the rotating polishing surface to assist the planarization process.
During polishing process, chemical fume, vapor from the polishing solution, and other byproducts may generate and diffuse around the platen, polishing head and other devices impairing system cleanness, introducing defects and cross contamination among platens and substrates.
Conventional polishing system generally have a top exhaust or a bottom exhaust for the entire system, usually comprising at least several platens, several polishing heads, one or more load cups, one or more platen conditioners. The chemical fume, vapor and other byproducts generally need to travel across the system before entering the exhaust. As a result, a portion of chemical fume, vapor, and other byproducts would condense and remain on surfaces of the system. The condensed matter usually dries on the surfaces affecting the appearance. Moreover, dried polishing solution becomes flaky and causes defects in the substrate during processing.
Therefore, there is a need for apparatus and method to effectively remove the chemical fume, vapor, and other byproducts generated during a polishing process.